The research proposed is directed to the development and application of improved immunologic techniques for detection and quantification of carcinoembryonic antigen (CEA) and human antibody directed against this antigen. The proposed techniques utilize antigen and/or antibody preparations insolubilized to immunoadsorbents thereby facilitating separation of free from bound antigens or antibodies. Antigen-antibody complexes are detected by means of enzyme amplification. The simplified methods proposed may be extended to clinical and hospital laboratories not equipped for use of radioisotopes. Use of the proposed methods should permit greatly enlarged screening programs for CEA and anti-CEA. With enlarged screening programs, the relationships between CEA and colonic adenocarcinoma will be more clearly understood and early detection of cancer of the large bowel may be realized.